Displaying publications 21 - 40 of 360 in total

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  1. Surface phonon polariton characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure
    Ng SS, Lee SC, Bakhori SK, Hassan Z, Abu Hassan H, Yakovlev VA, et al.
    Opt Express, 2010 May 10;18(10):10354-9.
    PMID: 20588890 DOI: 10.1364/OE.18.010354
    Surface phonon polariton (SPP) characteristics of In(0.04)Al(0.06)Ga(0.90)N/AlN/Al(2)O(3) heterostructure are investigated by means of p-polarized infrared (IR) attenuated total reflection spectroscopy. Two absorption dips corresponding to In(0.04)Al(0.06)Ga(0.90)N SPP modes are observed. In addition, two prominent dips and one relatively weak and broad dip corresponding to the Al(2)O(3) SPP mode, In(0.04)Al(0.06)Ga(0.90)N/Al(2)O(3) interface mode, and Al(2)O(3) bulk polariton mode, respectively, are clearly seen. No surface mode feature originating from the AlN layer is observed because it is too thin. Overall, the observations are in good agreement with the theoretical predictions.
  2. Fulltext MUSiC: a model-unspecific search for new physics in proton-proton collisions at s = 13 TeV
    CMS Collaboration, Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, et al.
    Eur Phys J C Part Fields, 2021;81(7):629.
    PMID: 34727144 DOI: 10.1140/epjc/s10052-021-09236-z
    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV , corresponding to an integrated luminosity of 35.9 fb - 1 , are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.
  3. Fulltext Search for dark matter produced in association with a leptonically decaying Z boson in proton-proton collisions at s = 13 Te
    Sirunyan AM, CMS Collaboration, Tumasyan A, Adam W, Bergauer T, Dragicevic M, et al.
    Eur Phys J C Part Fields, 2021;81(1):13.
    PMID: 33493254 DOI: 10.1140/epjc/s10052-020-08739-5
    A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton-proton collision data at a center-of-mass energy of 13 Te , collected by the CMS experiment at the LHC in 2016-2018, corresponding to an integrated luminosity of 137 fb - 1 . The search uses the decay channels Z → e e and Z → μ μ . No significant excess of events is observed over the background expected from the standard model. Limits are set on dark matter particle production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as on a two-Higgs-doublet model with an additional pseudoscalar mediator. In addition, limits are provided for spin-dependent and spin-independent scattering cross sections and are compared to those from direct-detection experiments. The results are also interpreted in the context of models of invisible Higgs boson decays, unparticles, and large extra dimensions.
  4. Fulltext Measurements of production cross sections of the Higgs boson in the four-lepton final state in proton-proton collisions at s = 13 TeV
    CMS Collaboration, Sirunyan AM, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, et al.
    Eur Phys J C Part Fields, 2021;81(6):488.
    PMID: 34727143 DOI: 10.1140/epjc/s10052-021-09200-x
    Production cross sections of the Higgs boson are measured in the H → Z Z → 4 ℓ ( ℓ = e , μ ) decay channel. A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV , collected by the CMS detector at the LHC and corresponding to an integrated luminosity of 137 fb - 1 is used. The signal strength modifier μ , defined as the ratio of the Higgs boson production rate in the 4 ℓ channel to the standard model (SM) expectation, is measured to be μ = 0.94 ± 0.07 (stat) - 0.08 + 0.09 (syst) at a fixed value of m H = 125.38 GeV . The signal strength modifiers for the individual Higgs boson production modes are also reported. The inclusive fiducial cross section for the H → 4 ℓ process is measured to be 2 . 84 - 0.22 + 0.23 (stat) - 0.21 + 0.26 (syst) fb , which is compatible with the SM prediction of 2.84 ± 0.15 fb for the same fiducial region. Differential cross sections as a function of the transverse momentum and rapidity of the Higgs boson, the number of associated jets, and the transverse momentum of the leading associated jet are measured. A new set of cross section measurements in mutually exclusive categories targeted to identify production mechanisms and kinematical features of the events is presented. The results are in agreement with the SM predictions.
  5. Fulltext Adult embryonal rhabdomyosarcoma of the ethmoid: a rare entity
    Rohaizam J, Doris EJ, Tang PI, Lee SC, Uchang J
    Med J Malaysia, 2010 Jun;65(2):160-1.
    PMID: 23756807 MyJurnal
    Embryonal rhabdomyosarcoma is an exceedingly rare tumor in adult. We report an embryonal rhabdomyosarcoma of the ethmoid in a 59-year-old Iban lady who presented with proptosis and complete ptosis of her left eye for two months. Imaging investigations showed left ethmoidal and left orbital soft tissue mass with extradura and dura involvement. The patient was planned for chemotherapy. Unfortunately, in such an advanced disease, she succumbed before treatment.
  6. Comparison of the fine-scale genetic structure of three dipterocarp species
    Takeuchi Y, Ichikawa S, Konuma A, Tomaru N, Niiyama K, Lee SL, et al.
    Heredity (Edinb), 2004 Apr;92(4):323-8.
    PMID: 14735142
    We investigated the fine-scale genetic structure of three tropical-rainforest trees, Hopea dryobalanoides, Shorea parvifolia and S. acuminata (Dipterocarpaceae), in Peninsular Malaysia, all of which cooccurred within a 6-ha plot in Pasoh Forest Reserve. A significant genetic structure was found in H. dryobalanoides, weaker (but still significant) genetic structure in S. parvifolia and nonsignificant structure in S. acuminata. Seeds of all three species are wind dispersed, and their flowers are thought to be insect pollinated. The most obvious difference among these species is their height: S. parvifolia and S. acuminata are canopy species, whereas H. dryobalanoides is a subcanopy species. Clear differences were also found among these species in their range of seed dispersal, which depends on the height of the release point; so taller trees disperse their seed more extensively. The estimates of seed dispersal area were consistent with the degree of genetic structure found in the three species. Therefore, tree height probably had a strong influence on the fine-scale genetic structure of the three species.
  7. Fulltext Secular trends of health care resource utilization and costs between Brugada syndrome and congenital long QT syndrome: A territory-wide study
    Lee S, Chung CTS, Radford D, Chou OHI, Lee TTL, Ng ZMW, et al.
    Clin Cardiol, 2023 Oct;46(10):1194-1201.
    PMID: 37489866 DOI: 10.1002/clc.24102
    BACKGROUND: Health care resource utilization (HCRU) and costs are important metrics of health care burden, but they have rarely been explored in the setting of cardiac ion channelopathies.

    HYPOTHESIS: This study tested the hypothesis that attendance-related HCRUs and costs differed between patients with Brugada syndrome (BrS) and congenital long QT syndrome (LQTS).

    METHODS: This was a retrospective cohort study of consecutive BrS and LQTS patients at public hospitals or clinics in Hong Kong, China. HCRUs and costs (in USD) for Accident and Emergency (A&E), inpatient, general outpatient and specialist outpatient attendances were analyzed between 2001 and 2019 at the cohort level. Comparisons were made using incidence rate ratios (IRRs [95% confidence intervals]).

    RESULTS: Over the 19-year period, 516 BrS (median age of initial presentation: 51 [interquartile range: 38-61] years, 92% male) and 134 LQTS (median age of initial presentation: 21 [9-44] years, 32% male) patients were included. Compared to LQTS patients, BrS patients had lower total costs (2 008 126 [2 007 622-2 008 629] vs. 2 343 864 [2 342 828-2 344 900]; IRR: 0.857 [0.855-0.858]), higher costs for A&E attendances (83 113 [83 048-83 177] vs. 70 604 [70 487-70 721]; IRR: 1.177 [1.165-1.189]) and general outpatient services (2,176 [2,166-2,187] vs. 921 [908-935]; IRR: 2.363 [2.187-2.552]), but lower costs for inpatient stay (1 391 624 [1 391 359-1 391 889] vs. 1 713 742 [1 713 166-1 714 319]; IRR: 0.812 [0.810-0.814]) and lower costs for specialist outpatient services (531 213 [531 049-531 376] vs. 558 597 [558268-558926]; IRR: 0.951 [0.947-0.9550]).

    CONCLUSIONS: Overall, BrS patients consume 14% less health care resources compared to LQTS patients in terms of attendance costs. BrS patients require more A&E and general outpatient services, but less inpatient and specialist outpatient services than LQTS patients.

  8. Vision loss in an immunocompetent child post varicella infection: A case report
    Lee SC, Ng M, Tan CL, Ting SL
    Malays Fam Physician, 2020;15(1):54-57.
    PMID: 32284807
    Chickenpox may lead to several neurological complications. Optic neuritis is one of the complications which has rarely been described, especially in immunocompetent individuals. We report a case of an 11-year-old immunocompetent girl who presented with sudden onset bilateral vision loss three weeks after varicella eruption. Ophthalmic examination revealed bilateral optic disc edema. Diagnosis of bilateral optic neuritis secondary to varicella was established based upon the preceding medical history, supported with clinical and radiological findings.
  9. Adolescents as perpetrators of aggression within the family
    Kuay HS, Lee S, Centifanti LC, Parnis AC, Mrozik JH, Tiffin PA
    Int J Law Psychiatry, 2016 Jul-Aug;47:60-7.
    PMID: 27016774 DOI: 10.1016/j.ijlp.2016.02.035
    Although family violence perpetrated by juveniles has been acknowledged as a potentially serious form of violence for over 30years, scientific studies have been limited to examining the incidence and form of home violence. The present study examined the prevalence of family aggression as perpetrated by youths; we examined groups drawn from clinic-referred and forensic samples. Two audits of case files were conducted to systematically document aggression perpetrated by referred youths toward their family members. The purpose of the first audit was fourfold: i) to identify the incidence of the perpetration of family aggression among clinical and forensic samples; ii) to identify whether there were any reports of weapon use during aggressive episodes; iii) to identify the target of family aggression (parents or siblings); and iv) to identify the form of aggression perpetrated (verbal or physical). The second audit aimed to replicate the findings and to show that the results were not due to differences in multiple deprivation indices, clinical diagnosis of disruptive behavior disorders, and placement into alternative care. A sampling strategy was designed to audit the case notes of 25 recent forensic Child and Adolescent Mental Health Service (CAMHS) cases and 25 demographically similar clinic-referred CAMHS cases in the first audit; and 35 forensic cases and 35 demographically similar clinic-referred CAMHS cases in the second audit. Using ordinal chi-square, the forensic sample (audit 1=64%; audit 2=82.9%) had greater instances of family violence than the clinical sample (audit 1=32%; audit 2=28.6%). They were more likely to use a weapon (audit 1=69%; audit 2=65.5%) compared to the clinical sample (audit 1 and 2=0%). Examining only the aggressive groups, there was more perpetration of aggression toward parents (audit 1, forensic=92%, clinical=75%; audit 2, forensic=55.17%, clinical=40%) than toward siblings (audit 1, forensic=43%, clinical=50%; audit 2, forensic=27.58%, clinical=30%). Based on these findings, we would urge professionals who work within the child mental health, particularly the forensic area, to systematically collect reports of aggression perpetrated toward family members.

    Study conducted in England
  10. Translational aspects of genetic factors in the prediction of drug response variability: a case study of warfarin pharmacogenomics in a multi-ethnic cohort from Asia
    Chan SL, Suo C, Lee SC, Goh BC, Chia KS, Teo YY
    Pharmacogenomics J, 2012 Aug;12(4):312-8.
    PMID: 21383771 DOI: 10.1038/tpj.2011.7
    Genetic markers displaying highly significant statistical associations with complex phenotypes may not necessarily possess sufficient clinical validity to be useful. Understanding the contribution of these markers beyond readily available clinical biomarkers is particularly important in pharmacogenetics. We demonstrate the utility of genetic testing using the example of warfarin in a multi-ethnic setting comprising of three Asian populations that are broadly representative of the genetic diversity for half of the population in the world, especially as distinct interethnic differences in warfarin dose requirements have been previously established. We confirmed the roles of three well-established loci (CYP2C9, VKORC1 and CYP4F2) in explaining warfarin dosage variation in the three Asian populations. In addition, we assessed the relationship between ethnicity and the genotypes of these loci, observing strong correlations at VKORC1 and CYP4F2. Subsequently, we established the additional utility of these genetic factors in predicting warfarin dose beyond ethnicity and clinical biomarkers through performing a series of systematic cross-validation analyses of the relative predictive accuracies of various fixed-dose regimen, clinical and genetic models. Through a pharmacogenetics model for warfarin, we show the importance of genetic testing beyond readily available clinical biomarkers in predicting dose requirements, confirming the role of genetic profiling in personalized medicine.
  11. Fulltext Evaluation of BRCA1 and BRCA2 mutations and risk-prediction models in a typical Asian country (Malaysia) with a relatively low incidence of breast cancer
    Thirthagiri E, Lee SY, Kang P, Lee DS, Toh GT, Selamat S, et al.
    Breast Cancer Res, 2008;10(4):R59.
    PMID: 18627636 DOI: 10.1186/bcr2118
    The cost of genetic testing and the limited knowledge about the BRCA1 and BRCA2 genes in different ethnic groups has limited its availability in medium- and low-resource countries, including Malaysia. In addition, the applicability of many risk-assessment tools, such as the Manchester Scoring System and BOADICEA (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm) which were developed based on mutation rates observed primarily in Caucasian populations using data from multiplex families, and in populations where the rate of breast cancer is higher, has not been widely tested in Asia or in Asians living elsewhere. Here, we report the results of genetic testing for mutations in the BRCA1 or BRCA2 genes in a series of families with breast cancer in the multi-ethnic population (Malay, Chinese and Indian) of Malaysia.
  12. Identification of germline alterations in breast cancer predisposition genes among Malaysian breast cancer patients using panel testing
    Ng PS, Wen WX, Fadlullah MZ, Yoon SY, Lee SY, Thong MK, et al.
    Clin Genet, 2016 10;90(4):315-23.
    PMID: 26757417 DOI: 10.1111/cge.12735
    Although an association between protein-truncating variants and breast cancer risk has been established for 11 genes, only alterations in BRCA1, BRCA2, TP53 and PALB2 have been reported in Asian populations. Given that the age of onset of breast cancer is lower in Asians, it is estimated that inherited predisposition to breast cancer may be more significant. To determine the potential utility of panel testing, we investigated the prevalence of germline alterations in 11 established and 4 likely breast cancer genes in a cross-sectional hospital-based cohort of 108 moderate to high-risk breast cancer patients using targeted next generation sequencing. Twenty patients (19%) were identified to carry deleterious mutations, of whom 13 (12%) were in the BRCA1 or BRCA2, 6 (6%) were in five other known breast cancer predisposition genes and 1 patient had a mutation in both BRCA2 and BARD1. Our study shows that BRCA1 and BRCA2 account for the majority of genetic predisposition to breast cancer in our cohort of Asian women. Although mutations in other known breast cancer genes are found, the functional significance and breast cancer risk have not yet been determined, thus limiting the clinical utility of panel testing in Asian populations.
  13. Benign lymphoepithelial lesion of the submandibular glands
    Lee ST, Raman R, Tay A
    Otolaryngol Head Neck Surg, 1987 Dec;97(6):580-2.
    PMID: 3155441
  14. Confluent and reticulated papillomatosis: Case series of 3 patients from Kedah, Malaysia and literature review
    Lee SW, Loo CH, Tan WC
    Med J Malaysia, 2018 10;73(5):338-339.
    PMID: 30350820 MyJurnal
    Confluent and reticulated papillomatosis (CRP) was first described in 1927 by Gougerot and further characterised by Carteud.1 It is relatively rare, and the exact pathophysiology was not well known. Over the years, multiple treatment modalities were proposed. We report our experience with three cases of CRP which showed complete clearance with tetracycline group of antibiotics.
  15. Fulltext Head and neck cancer: possible causes for delay in diagnosis and treatment
    Lee SC, Tang IP, Avatar SP, Ahmad N, Selva KS, Tay KK, et al.
    Med J Malaysia, 2011 Jun;66(2):101-4.
    PMID: 22106686 MyJurnal
    To explore the possible causes for delay in diagnosis and treatment of head and neck cancer at Sarawak General Hospital (SGH).
  16. PXR, CAR and HNF4alpha genotypes and their association with pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin in Asian patients
    Hor SY, Lee SC, Wong CI, Lim YW, Lim RC, Wang LZ, et al.
    Pharmacogenomics J, 2008 Apr;8(2):139-46.
    PMID: 17876342
    Previously studied candidate genes have failed to account for inter-individual variability of docetaxel and doxorubicin disposition and effects. We genotyped the transcriptional regulators of CYP3A and ABCB1 in 101 breast cancer patients from 3 Asian ethnic groups, that is, Chinese, Malays and Indians, in correlation with the pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin. While there was no ethnic difference in docetaxel and doxorubicin pharmacokinetics, ethnic difference in docetaxel- (ANOVA, P=0.001) and doxorubicin-induced (ANOVA, P=0.003) leukocyte suppression was observed, with Chinese and Indians experiencing greater degree of docetaxel-induced myelosuppression than Malays (Bonferroni, P=0.002, P=0.042), and Chinese experiencing greater degree of doxorubicin-induced myelosuppression than Malays and Indians (post hoc Bonferroni, P=0.024 and 0.025). Genotyping revealed both PXR and CAR to be well conserved; only a PXR 5'-untranslated region polymorphism (-24381A>C) and a silent CAR variant (Pro180Pro) were found at allele frequencies of 26 and 53%, respectively. Two non-synonymous variants were identified in HNF4alpha (Met49Val and Thr130Ile) at allele frequencies of 55 and 1%, respectively, with the Met49Val variant associated with slower neutrophil recovery in docetaxel-treated patients (ANOVA, P=0.046). Interactions were observed between HNF4alpha Met49Val and CAR Pro180Pro, with patients who were wild type for both variants experiencing least docetaxel-induced neutropenia (ANOVA, P=0.030). No other significant genotypic associations with pharmacokinetics or pharmacodynamics of either drug were found. The PXR-24381A>C variants were significantly more common in Indians compared to Chinese or Malays (32/18/21%, P=0.035) Inter-individual and inter-ethnic variations of docetaxel and doxorubicin pharmacokinetics or pharmacodynamics exist, but genotypic variability of the transcriptional regulators PAR, CAR and HNF4alpha cannot account for this variability.
  17. Evaluation of live renal donors with three-dimensional contrast-enhanced magnetic resonance angiography in comparison to catheter angiography
    Tan SP, Bux SI, Kumar G, Razack AH, Chua CB, Lee SH, et al.
    Transplant Proc, 2004 Sep;36(7):1914-6.
    PMID: 15518697
    Catheter angiography is traditionally used to determine renal arterial anatomy in live renal donors. Three-dimensional (3D) contrast-enhanced magnetic resonance imaging (MRA) has been suggested as a noninvasive replacement. We assessed the possibility of using MRA in live renal donors in Malaysia.
  18. DNA-templated silver nanoclusters: structural correlation and fluorescence modulation
    New SY, Lee ST, Su XD
    Nanoscale, 2016 Oct 20;8(41):17729-17746.
    PMID: 27722695
    12 years after the introduction of DNA-templated silver nanoclusters (DNA-AgNCs), exciting progress has been made and yet we are still in the midst of trying to fully understand this nanomaterial. The prominent excellence of DNA-AgNCs is undoubtedly its modulatable emission property, of which how variation in DNA templates causes emission tuning remains elusive. Based on the up-to-date DNA-AgNCs, we aim to establish the correlation between the structure/sequence of DNA templates and emission behaviour of AgNCs. Herein, we systematically present a wide-range of DNA-AgNCs based on the structural complexity of the DNA templates, including single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), triple-stranded DNA (tsDNA) and DNA nanostructures. For each DNA category, we discuss the emission property, quantum yield and synthesis condition of the respective AgNCs, before cross-comparing the impact of different DNA scaffolds on the properties of AgNCs. A future outlook for this area is given as a conclusion. By putting the information together, this review may shed new light on understanding DNA-AgNCs while we are expecting continuous breakthroughs in this field.
  19. Total perineal reconstruction after major obstetrical injuries with extensive tissue loss: a report of 2 cases
    Lee SH, Cheah DS, Poopalarachagan S, Sivanesaratnam V
    Aust N Z J Obstet Gynaecol, 1991 Nov;31(4):372-5.
    PMID: 1799358
    Major perineal injuries following obstetrical complications represent difficult problems of reconstruction. We describe 2 such patients with perineal injuries simulating infantile cloacas. Surgical repair using an abdominoperineal pullthrough procedure in 1 patient, and a Bricker loop type of repair in another resulted in successful restoration of function in both. The operative details and basis for the reconstruction are described.
  20. Fulltext Spontaneous Conventional Osteosarcoma Transformation of a Chondroblastoma: A Case Report and Literature Review
    Narhari P, Haseeb A, Lee S, Singh VA
    Indian J Orthop, 2018 2 9;52(1):87-90.
    PMID: 29416176 DOI: 10.4103/ortho.IJOrtho_495_17
    Chondroblastomas are a primary benign cartilaginous tumor that accounts for approximately 1% of all benign bone tumors. Primarily they are treated by curettage. The patient presented 4 years after a successfully treated chondroblastoma (curettage and Bone cement). Wide resection of the proximal tibia with endoprosthesis replacement was done. Lung CT showed multiple lung metastasis and despite starting chemotherapy, he succumbed to the disease. We discuss regarding the possibilities of "aggressive" chondroblastoma and more recently termed chondroblastoma-like osteosarcoma which is a separate entity from chondroblastoma. Aggressiveness in chondroblastoma can be 1 of 3 types as follows: 1. benign chondroblastoma with lung metastasis. 2. malignant chondroblastoma. 3. subsequent malignant transformation of benign chondroblastoma. We have attempted to review the literature and describe the "aggressive" chondroblastoma and chondroblastoma-like osteosarcoma in this report.
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